Scarifier tooth



March 10, 1936.

's. M. sToopY SCARIFIEEAIUTTOOTH Filed Sept. 24, 1951 2 Sheets-Sheet lIP75. Z.

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Patented Mar. 10, 1936 UNITED STATES PATENT OFFICE SCARIFIER TOOTH tionof California Application September 24, 1931, Serial No. 564,858

'7 Claims.

This invention relates to improvements in scarifying teeth, such asthose used upon road scrapers, rooters, steam shovel buckets, andanalogous constructions.

. It is becoming common practice to apply pieces of a hard abrasivesubstance to the forward sides of scarifier teeth used on road scrapers,rooters, steam shovel buckets and the like. Such pieces for example maybe tungsten carbide or their equivalent and are frequently applied tothe tooth by means of a welding rod, such as is disclosed in UnitedStates Letters Patent Nos. 1,757,601 and 1,803,875, wherein the piecesof tungsten carbide are enclosed within a mild steel tube. During thewelding operation the mild steel tube forms a matrix metal deposited onthe body of the tooth and fused thereto in which the pieces of abrasiveare embedded. When conventional forms of scarifier teeth have this hardfacing applied thereto several difficulties are frequently encountered.Many types of scarifier teeth are either circular or rectangular incross-section or may have other shapes which provide a relatively thickbody of steel having on its forward face the deposit of matrix metalcontaining the hard abrasive pieces. These teeth are frequentlysharpened to a chisel point in their initial construction and if theyare of other designs they frequently have a relatively thin bottom edge.When they start to cut, the chisel point or thin edge frequently becomesred hot, due to friction, and the steel body near the point approaches aforging temperature. The heat softens the steel sufficiently so that thepieces of tungsten carbide, or other hard abrasive, on the thin edge orchisel point are forced or carried rearwardly through the softenedmetal. These pieces on the point, therefore, become lost without havingaccomplished a great deal of cutting. Following this action in which thepoint or thin edge is quickly worn, there usually is a short period offairly good wear and good cutting. Theoretically as the body of thescarifier tooth is formed of steel, which is much softer than the piecesof tungsten carbide, it should wear away faster than the tungstencarbide and cause the scarifier tooth to be self-sharpening. However,when the scarifier tooth is cylindrical in form or has a rectangularcross-section, or has a relatively thick body of other shape, the largemass of steel behind the deposit of abrasive is too large to be wornaway fast enough to accomplish the self-sharpening action. Consequentlyit frequently occurs that this relatively large body of steel behind theabrasive is worn into a rounded heel on the bottom of the tooth. Whenthe rounded heel is formed it merely rubs and prevents cutting. A greatdeal of friction is created and the tooth has a tendency to chatter. Thepieces of tungsten carbide under these conditions cannot cut effec- 5tively and instead of being worn off are frequently knocked off andlost.

It is an object of the present invention to provide an improvedscarifier tooth having a protecting hard abrasive substance onitsforward side and which is so designed that the formation of the roundedheel is effectively prevented. In this way the body of the tooth iscaused to wear away practically uniformly at a rate faster than the hardabrasive substance wears. As a result, the rounded heel does not formand the scarifier tooth is self-sharpening. The chattering of the toothis prevented and the length of life of the tooth is materially prolongedin that each piece of abrasive is caused to wear away completely withoutbeing subject to the danger of being knocked off and lost.

Another object of the invention is to provide a scarifier tooth, oranalogous construction, which has an initial sharp point so designedthat the pieces of tungsten carbide on the point will be efiectivelybacked by steel so that they cannot be forced through the steel andlost.

It has been proposed to design a scarifier tooth for road scrapers andanalogous constructions in which the tooth has a body somewhat similarto the conventional plow. When a tooth of this design has a hard facingapplied to its forward face, only a relatively small period ofsatisfactory wear is possible. This is due to the fact that the body ofthe tooth is not of uniform cross-sectional shape and area. It graduallyincreases in size and shape from bottom to top of the scarifying end.Consequently when the tooth becomes badlyworn, the upper portion of thebody being larger and thicker is apt to wear into the form of a roundedheel with the incidental disadvantages above mentioned. In suchconstruction whenever the scarifying endof the tooth becomes badly wornit is necessary to either rebuild the tooth or to junk it. The designsof such type of teeth also are disadvantageous in that the bottom of thebody is usually too thin to prevent the pieces of tungsten carbide frombeing carried through the steel when heated to a forging temperature.

Another object of the present invention is to provide an improvedscarifier tooth which is of uniform cross-sectional shape and area sothat its cutting action and wearing action will be identical throughoutthe complete scarifying end 55 of the tooth. In other words the cuttingand wearing of the tooth will be substantially the same when the toothfirst starts cutting as when it has become badly worn.

Another object of the invention is to provide a scarifier tooth, thescarifying end of which is substantially V shaped in cross-section,having a hard abrasive material mounted on the apex thereof and havingprotective side facings extending rearwardly on the sides of thescarifying end. These side facings not only protect the body of thetooth. preserving a good support for the abresive on the apex, but theyalso serve to form sharp edges on the bottoms of the sides of the toothwhich will facilitate penetrating, that is the entering action of thescarifier tooth into the road or the formation as the case may be.

Still a further object of the invention is to provide a novelconstruction of scarifier tooth or steam shovel bucket tooth having anabrasive mounted on the forward side of the tooth and to provide a novelconstruction assisting in anchoring the abrasive to the tooth so that itcannot be easily knocked off.

With the foregoing and other objects in view, which will be mademanifest in the following detailed description, and specifically pointedout in the appended claims, reference is bad to the accompanyingdrawings for an illustrative embodiment of the invention, wherein:

Fig. 1 is a side elevation of a scarifier tooth such as is employed onroad scrapers embodying the invention, parts being broken away'and shownin vertical section.

Fig. 2 is a sectional view taken substantially upon the line 22 uponFigure 1.

Fig. 3 is a view similar to Figure 1 illustrating a slightly modifiedform of scraper tooth.

Fig; 4 is a sectional viewsimilar to Figure. 2 illustrating a slightmodification.

Fig. 5 is another view in side elevation of another modification, partsbeing broken away and shown in vertical section.

Fig. 6 is a sectional view illustrating a detail of construction whichmay be employed.

Fig. 7 is a partial perspective view illustrating another modified formembodying the invention.

Fig. 8 is a sectional view through a steam shovel bucket illustratingthe invention as having been incorporated in a steam shovel buckettooth.

Fig. 9 is a sectional view through the steam shovel bucket tooth.

Referring to the accompanying drawings, wherein similar referencecharacters designate similar parts throughout, the scarifier toothillustrated in Figure l is of the double ended type, either of whichends may be employed. It consists of a shank l0 having an upperscarifying end II and a lower scarifying end 12. The lower scarlfyingend, which is the one being used, extends downwardly and forwardly aconsiderable distance from the lower end of the shank so that itencounters the horizontal, forming an angle of approximately 48therewith. This angle may vary under different circumstances butpreferably is between 35 and 55 degrees. As clearly shown on Figure 2,the scarifying end is V shaped in cross-section having rearwardlydivergent sides 13 and I4 defined from each other by a groove I5 whichextends the complete length of the scarifying end. On the apex orforward side of the tooth there is formed a groove IS within which thereis deposited as by welding a relatively heavy deposit of hard facing orabrasive II. This deposit is preferably produced by using a welding rodas disclosed in prior United States Patents Nos. 1,757,601 and1,803,875. Any other suitable manner or suitable abrasive may beemployed if so desired. When the mentioned welding rod is used, a mildsteel matrix is deposited in the groove 16 in which particles of a hardsubstance; such as tungsten carbide indicated at I8, are embedded. Thisdeposit extends upwardly the complete length of the scarifying end andthe facing preferably continues a short distance up on the forward sideof the shank as indicated at l 9. In the preferred form of constructiona relatively thin facing 20 extends rearwardly along the sides l3 and M.This facing may extend entirely to the rear end of each side l3 and Mbut this is not essential and the side facings 20 may extend onlypartially over the sides l3 and I4 as shown. It will be noted that thebody of the scarifying tooth provides a certain thickness of steelbehind the heavy forward hard facing at IT. The thickness of the steelat this point is much less than the overall width or depth of thescarifying end. Likewise the thickness from front to back through thesides l3 and I4 is approximately equal to the thickness of the toothbetween grooves l5 and l 6 so that there is practically a uniformthickness of steel behind the hard facings I1 and 20. With thisconstruction the tooth tapers forwardly and has a very hard abrasiveforward edge on the apex. As the back of the tooth is removed in formingthe groove I5, there is no large body of steel behind the abrasive ingroove 16 to form the rounded heel. Wear of the body of the tooth ispractically uniform both at the center of the tooth and over the sidesl3 so that the tooth will be in effect self-sharpening, wearing awayfaster than the hard facings l1 and 20. Each scarifying end is uniformin cross-sectional shape and area from bottom to top so that there willbe substantially the same cutting and wearing action taking place whenthe scarifier tooth is originally used as when it has become badly worn.The thick backing behind the very bottom of the hard facing I1 issufficient to prevent pieces of tungsten carbide from being driventhrough the body and becoming lost even in the event that the toothbecomes red hot during use. As the body of the tooth can wear awayequally behind the side facings 20, these side facings will form sharpedges on the sides of the tooth which facilitate penetration or theentering of the tooth into the road.

In the modification shown in Figure 1, when one scarifying end iscompletely worn away, the tooth can be reversed to use the otherscarifying end. Some forms of road scraping machines, however, are sodesigned as to be incapable of using a double ended tooth and for thispurpose a single ended tooth as shown in Figure 3 is provided, having ashank 25 and a single scarifying end 26, which is of the sameconstruction as that previously described in conjunction with scarifyingend l2. scarifying tooth may be straight. Such a tooth is indicated inFigure 5 having a straignt shank 30 in alignment with the two scarifyingends illustrated at 3| and 32. These scarifying ends are likewisesimilar to the scarifying end I 2.

As a modified form of construction, there is illustrated in Figure 4 thecross-section of a scarifying end which is V shaped having a centerportion 35 in the apex of which there is provided a groove 36. Thisgroove is filled with a hard facing 31 similar to the hard facing 11.However, this construction is shown as having the side In other types ofmachines the facings omitted. It is possible under certain conthanfacing I! this facing wears away somewhat faster than facing l1 and willbring about a uniform even wear of the tooth.

- In certain forms of construction the tooth must be very heavily faced.This is particularly true when the tooth happens to be quite large. Forthis purpose the scarifying end is given a V shape cross-sectionillustrated at on Figure 6 and on the apex there are formed a series ofrelatively deep grooves 4|. These grooves .are shown as being deeperthan they are wide. Additional grooves 42 may be formed on' the sideswhich are somewhat shallower. These grooves are filled with the hardfacing 43 and a coat or layer of the hard facing may be applied to thesides and over the apex. The purpose of this construction is as follows.If groove I6 is too large it is possible for the facing to be knockedout or gouged out of the groove in doing very heavy work. Where theconstruction illustrated in Figure 6 is employed, the hard facing may bebroken off but because of the very deep grooves the hard facing cannotbe completely removed therefrom. Consequently even in the event that thehard facing is chipped away some hard facing remains to cut effectively.

The large areas on the sides of the grooves likewise greatly facilitatethe forming of a good adhesive bond between the deposit and the body ofthe tooth.

In Figure 'I there is illustrated another form of construction designedfor heavy work. In this construction the tooth has a V shaped scarifyingend, the apex having a groove 45. Pins 46 are cast integral with thebody of the tooth and are deposited within thisgroove. These pins may bearranged in a row or may be staggered. Smaller pins 41 may be cast onthe sides. When the hard facing is welded on it is welded around thesepins and over them. Their presence assists greatly in anchoring the hardfacing to the tooth.

In Figures 8 and 9 the invention is illustrated as having beenincorporated on a tooth for steam shovel buckets. A conventional steamshovel bucket is indicated at 50 having teeth applied thereto, eachtooth having a shank 5| which is bifurcated as indicated at 52- Boltholes 53 permit the insertion of bolts 54 for attaching the tooth to thebucket. The scarifying end of the tooth extends downwardly and forwardlyand is V shaped in cross-section. The scarifying end indicated at'55 isillustrated as beingof the same construction as the scarifying end l2.However,

it may be of the design illustrated in either Figure 4, 6 or 7, ifdesired. It hasbeen found that a steam shovel bucket tooth constructedin the manner illustrated lasts materially longer than the conventionalsteam shovel bucket teeth now in general use. Furthermore the end of thetooth remains sharp due to the self-sharpening action which is takingplace during wear. This scarifying end of the steam shovel bucket toothis likewise of uniform section throughout a substantial portion of itslength to cause the wear to be uniform and'to prevent the formation of arounded heel during any period of its wear.

While the various forms of construction illustrate the tooth as having agroove on its apex, the

presence of the groove is not absolutely essential. In some instancesthe groove may be omitted and merely a heavy coating of hard facingapplied to the apex. The groove is preferable, however, due to the factthat it facilitates welding the hard facing onto the tooth and also hasthe tendency to prevent the hard facing from being knocked off.

Various changes may be made in the details of construction withoutdeparting from the spirit or scope of the invention as defined by theappended claims.

I claim:

1. A scarifler tooth for road scrapers and the like having a scariflerend of uniform cross-sectional shape and area, the center of thescarifying end being arrangedjoremost, and the sides ex tendingrearwardly therefrom, the front to back thicknesses of the center andthe sides being approximately equal, pieces of a hard abrasive mountedin a groove on the forward side of the center portion, and 'a coating ofabrasive extending partially toward the rear of the sides, said coatingbeing thinner than the pieces of abrasive in the groove.

2. A scarifler tooth having a, series of grooves on its forward side, atleast some of the grooves being deeper than wide, and a hard abrasivesubstance filling said grooves.

3. A scarifier tooth having projecting pins on its forward side, and anabrasive substance deposited over and around said pins so as to beanchored to the tooth thereby.

4. A scarifier tooth having a longitudinally extending groove'in itsleading edge, wearing material in said groove and on those faces of thetooth which are adjacent the groove, said wearing material comprisingtungsten-carbide particles and a binder integrally fused to the tooth.

-5. A scarifler tooth or the like comprising a longitudinally extendingbody having forwardly converging sides converging toward its center,there being a plurality of longitudinally extending grooves formed inthe body on the forward side thereof between the forwardly convergingsides, and a protective facing comprising pieces of a hard substancesuch as tungsten carbide .embedded in a matrix metal filling thegrooves, the matrix metal being fused tothe body of the tooth.

6. A scarifier tooth or the like comprising a longitudinally extendingbody having forwardly converging sides converging toward its center,there being a plurality of longitudinally extending grooves formed inthe body on the forward side thereof between the forwardly convergingsides, and a protective facing comprising pieces of a hard substancesuch as tungsten carbide embedded in a matrix metal filling the grooves,the matrix metal being fused to the body of the tooth,

the facings in adjacent grooves being connected forward side of the bodybetween said forwardly 'canverging sides, and a protective facingfilling said groove and extending rearwardly on the forwardly convergingsides, said facing comprising a hard substance embedded in a matrixmetal, the matrix metal being fused to the body of the tooth.

SHELLEY M. STOODY.

